## Comparison class


Represents a pointer to the method that compares two objects of the same type. This type should be allocated on stack and passed to functions by value or by reference. Never use [System::SmartPtr](../smartptr/) class to manage objects of this type.

```cpp
template<typename T>class Comparison : public System::MulticastDelegate<int(T, T)>
```


| Parameter | Description |
| --- | --- |
| T | The type of the objects the method compares |
## Methods

| Method | Description |
| --- | --- |
| [operator()](./operator()/)(T, T) | Invokes the invokable object pointed to by the current object. |
## Remarks



```cpp
#include "system/comparison.h"
#include "system/console.h"
#include "system/exceptions.h"
#include "system/string.h"
#include <algorithm>
#include <initializer_list>
#include <vector>

using namespace System;

// The template class that represents a dynamic array.
template <typename T>
class MyArray
{
  // Used to store the array data.
  std::vector<T> m_data;

public:
  // Constructs a new instance of our dynamic array.
  MyArray(const std::initializer_list<T>& source) : m_data(source) {};

  // Used to sort the array data. This method accepts an instance of the
  // 'System::Comparison' template class.
  void Sort(Comparison<T> comparison)
  {
    if (comparison.IsNull())
    {
      throw ArgumentNullException(u"comparison");
    }
    std::sort(m_data.begin(), m_data.end(), comparison);
  }

  // Returns a number of elements that our dynamic array stores.
  size_t get_Size()
  {
    return m_data.size();
  }

  // Used to get an element at the specified index.
  T& operator[](int index)
  {
    if (index < 0 || index >= m_data.size())
    {
      throw IndexOutOfRangeException(u"index");
    }
    return m_data[index];
  }
};

int main() {
  // Create an instance of the MyArray class with the specified elements.
  MyArray<String> arr = {u"a", u"e", u"c", u"b", u"d"};

  // Sort by ascending elements of the dynamic array.
  arr.Sort([](const String &a, const String &b) -> int
  {
    return String::Compare(a, b);
  });

  // Print elements of the dynamic array.
  for (auto i = 0; i < arr.get_Size(); ++i)
  {
    Console::WriteLine(arr[i]);
  }

  return 0;
}
/*
This code example produces the following output:
a
b
c
d
e
*/
```

## See Also

* Namespace [System](../)
* Library [Aspose.PDF for C++](../../)